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is-domain-name

is-domain-name

Validate Domain Names as outlined by RFC 2181

Install

npm install is-domain-name

Usage

Domain names are composed of labels interleaved with a separator (.). Domain as allowed a total length of 255 chars including separators. Labels should be between 1 and 63 octets.

Labels allows domains to form a hierarchy, with the right most label acting as the root. The leftmost label is often called the TLD (Top-Level Domain), the 2nd leftmost informally called the domain and any label to the right of those called subdomains.

A common domain with only a single label is localhost.

This module checks the following:

  • The domain is no longer than 255 chars
  • The domain is at least 2 chars. Even though a is technically allowed, this module does not allow it
  • Labels are between 1 and 63 chars
  • Labels start and end with alpha-numeric chars, allowing dashes in between
  • An optional root dot can be allowed with a flag, eg. example.com.
const assert = require('assert')
const isDomainName = require('is-domain-name')
 
assert.ok(isDomainName('localhost'))
assert.notOk(isDomainName('-.-'))

API

isDomainName(domainName, rootDot)

domainName

Type: String

rootDot

Type: Boolean
Default: false

Whether or not to validate for a trailing dot, signifying the root

Related

License

ISC